The present invention pertains to the deposition of transparent conductive layers, and more particularly to an improved charge-coupled optical imager having transparent conductive phase electrodes formed thereon by the plasma deposition of SnO.sub.2.
There are many applications which require the use of a layer of material which is both conductive as well as optically transparent, for example, solar cells, photodetectors, and semiconductor optical imagers. Frontside illuminated, semiconductor optical imagers, for example, require the use of conductive electrodes that completely cover the active surface of the device, but through which optical information must be allowed to pass for operation of the device. Metal oxide materials such as tin oxide and indium oxide are commonly used for this purpose.
Typically, tin oxide layers have been deposited by pyrolysis reactions, hydrolysis, R-F sputtering or CVD. Such processes have generally required high temperatures, and have not provided adequate uniformity of thickness or composition for purposes of fabricating CCD optical imaging devices.
Accordingly, it is a primary object of this invention to provide a low-temperature process for depositing SnO.sub.2 layers of uniform composition and thickness.